Method of manufacturing tire casings



smes

. INVENT'OR.

A. O. ABBOTT, JR

METHOD QF MANUFACTURING TIRE CA Filed March 15, 1928 Aug 16, 1932.

ly and wit 30 the gum contained in Patented Aug. 16, 1932 UNITED STATES mam o. anno'rn'm, or nmnorr, MICHIGAN, assmnoza 'ro monoan AND WEIGHT,"

PATENT OFFIC OF DETROIT, MICHIGAN, A GOBPORATIOH OF I METHOD OF'HANUFACTURING TIRE CASINOS Application filed larch 16, 1888. Serial No. 281,882.

for its primary object to increase the life of the tire by'the elimination of harmful action which enerally takes place between the various e ements and particularly the fabric plies.

In the forming of pneumatic tires by the flat or pulley band method, it ,is customary to superimpose two or more plies of rubberizedfabric, reinforce theseat the edges by bead wires and, by any of the well known formin methods, expand that portion between t e beads into tire shape. Other constituents of the tire may also be expanded in this operation but the present invention is concerned particularly with the action of the fabric plies.

It is generall recognized that the an Ice of the cords in til go changes during theshaping operation and the general tendencv of these changes is to conform to established laws of mechanics.

In practice it has been found that'in eve case where the normal cord spacin is suc that an an ular change cannot take p ace freellout considerable effort to displace the meshes formed by superimposing the plies in alternate thread angle relation, as commonly practiced at the present time, harmful action occursl This action causes an undue resistance to the pe- 85 ripheral elongation of the fabric envelope, resultm in an excessive change in the angular relation of-the cords in the alternate plles. Such resistance is more pronounced at the extreme periphery and graduates to a minimum 0 in the side wall of the formedtire. It is therefore advantageous to provide some means whereby the displacement of material in the cord meshes will be minimized, at the same time eliminating excessive strain on the cords and allowing them to take a more natural position in the formed tire. This may tion are free to slide over each other and thus reducing the resistance during the expande superimposed plies un er- J 1 be accomplished by providing lubricabetween adjacent plies so that the plies 'ingoperation. The tire is given a more natural and symmetrical shape than it assumes under the present conditions. This lubricant preferably should not'be detrimental to the adhesiveness of the rubber material after vulcanization. Therefore, the most advantageous material for this purpose is one which possesses lubricatingqualities at normal temperatures, but which is fused and absorbed y the rubber at vulcanization temperatures.

" Various forms of lubricant are suitable for this purpose'and particularly certain heavymetallic salts of the higher fatty acids, as for example, zinc stearate or metallic salts of arcmatic or hydroaromatic acids, as for example, zinc benzoate or zinc resinate. These substances in the small amounts required are sufficiently soluble in rubber as to be entirely absorbed thereby during vulcanization and the normal adhesiveness is restored to the surfgces upon which the lubricant was aping the lubricant to the tire elements, as for example, dusting it upon a surface in a dry state why applying it in suspension as a paint. The lubricant may be either applied to the entire contacting faces of the tire elements or to those zones where considerable movementofthe cords takes lace.

The many other. objects an advantages of the invention will be better understood by reference to the following specification when considered in connection with the accompanying drawing illustrating the principles Various methods may be utilized for apply- I inc V l views illustrating the movements pro-- duced by the expanding operation.

Referring to t a pneumatic tire with the present invention.

. superimposed with the cord angles alternat- .while it is upon this drum. The pulley band is then removed from the drum and expanded .in' any well known manner. The form after the expansion is illustrated in Fig. 3. The

tire thus formed is then vulcanized in the usual manner. In a general way,these steps on line the procedure in the building of a tire in accordance with the present invention.

I Iowever,-it will be appreciated that certain of these ste s may be very materially chan d v or even omitted and the principles of the invention ma methods. l iistead of applying the lubricant to a restricted zone, it will be evident that it may be applied throughout the width of the band but it has been found in practice that the zone indicated is suflicient- When the flat slab, as shown in Fig. 1 is placed upon the drum 15, no substantial chan e ta es place in the relative position or anguIar relation of the cords as the fabric is not stretched more than is necessary to fit it snugly about the drum. The change occurs during the expanding operation.

For the purpose of illustrating the movement of the cords during the expandin Operation, a series of diagrammatic -fi res ave been included in the drawing. Fig. 4 illus trates the approximate arrangement of the cords inadjacent plies (of whlch there may be any suitable number) at the completion of this operation. The arrangement in difl'erent zones of the tire are illustrated more in detail in Figs. 5,7 and 9 which re ctively show the zones in the vicinity of t e lines C-C, BB and A-A. A much"enlarged mesh from these zones of Figs. 5, 7 and 9 is res tively shown in Figs. 6, 8 and 10. Fig. 11 shows a mesh in a zone intermediate the zones of Figs. 5 and 7.

When the band has been expanded to tire form, the diameter of theinner periphery or that of zone AA has not changed, as this is the same as the diameter of the drum and therefore there has been no increase in the cord spacing. At the outer periphery, or zone 0-0, the spacing has materially ine drawings, Figs. 1-3 illustrate .one method of building in accordance .Strips of bias cut cord fabric as 12 and 13 are ing to form a flat slab. Zinc stearate or other be applied to various building mglchange in the cor it as been found that if the original cord angle designated by mately 51, the corresponding angle 5) in the zone CC will be 35. T creases gradually from the or zone A-A to the outer periphery or zone and the meshes pass through'corre' sponding progressive stages of change. In

approximately the original position of the cords or that of zone A-A, it will be seen from Fig. 10 that the parallelogram is longer radially than peripherally. In zone BB intermediate the .inner and outer peripheries, the radial di- .descreased' and the peripheral mension has dimension has correspondingly increased, as shown in Fi .8. At the outer periphery or zone CC, t e radial dimension is consider- .ably less than the peripheral, as shown in Fig. 6. Area F in the mesh formed by cords in adjacent plies, as shown in Fig. 8, is obviousl greater than the corresponding area G in the mesh of Fig. 10. Therefore, as the rubber is easily extensible, the resistance to this stage of expansion is slight. As the change progresses, there is little resistance until the position of Fig, 11 is reached for the area H approximately equals the area G, the height and length of the ing reversed but e ual. eyond this, the area diminishes as i lustrated at K (Fig. 6) and, in the absence of a lubricant, a crowding effect is produced which tends to displace the rubber component by compression, and the true peripheral spacing of the cords can be obtained only by a crowding of the cords into the rubber and a bulging of the rubber. This limits the peripheral expansion over a comlparatively wide lateral zone and-{heretofore as resulted in a flattened tread effect.

- If a lubricating substance be applied to the contacting faces of the plies of the carcass, either locally or over the entire area, according to the present invention the contiguous pllielsl 10f cords will be able to slip orshift s 1g t y in each ply willbe able to assume more nearly rfect geodetic lines between their-anchor W (Fig. 9) is zgpproxiarallelogram becreased and this has (produced a corresppndangles. For examples,

he spacing of the cords generally ininner periphery relative to one another, and the cords prior practice where no lubricating substance was used between the plies, the adhesiveness of-the rubber composition, restricted any or shifting of the cords in one ply relative to the cords in the neighboring ply. It is believed that at the .points where cords in nei hring plies cross one another the cords swing like a hinge on its pintle to some extent at least. In the present invention, on the other hand, the non-adhesiveness of the rubber prior to'vulcanization prevents to some extent, if not entirely, any such hinging movement of a cord in one ply relative to the oint' it crosses over the cord in the neighboring ply,

slip

and thus by not restricting the cords from assuming geodetic lines, permits the carcass assemblage to assume a more natural shape in the transformation from flat or pulleyband form to a proximately tire form. In

- made according to this invention, possesses V of a la ricant between the Where a lubricant is use which is fusible greater resiliency, flexibility and resistance to fati ue than one produced1 without the use res.

and soluble in the rubber at vulcanizing temperatures, this lubricant entirely disa pears during the vulcanization process and t e adhesive qualities of the rubber are restored prior to the completion of vulcanization. This. enables the elements to be permanently fixed in their expanded position by the vulcanization. While it has been found in practice that the use of a lubricant which is fusible and soluble in the rubber composition at the vulcanizing temperature thereof is usually advantageous, yet the present invention is not limited to the use of such a lubricant and the beneficial movement or ad'ustment of the cords may be obtained wit any substance permitting the desired movement of the cords during the shaping operation.

While the invention has been disclosedas applied to the manufacture of cord tire casings, in its broadest aspects it is not limited thereto, being applicable, withsome measure of advantage, to fabric casings. Likewise also in its broadest aspects, the invention is applicable ;to any tire building method on process'in which, after assembla e, there is at any time, an advantage in a ording the plies of the carcass greater freedom to movement. In the claims the term band form is employed broadly to cover flat building in distinguishing from core building.

Having thus described my invention what I claim and desire to protect by Letters Patent is:

1-. That method of manufacturing tire casing's which consists in, assembling constituent rubberized ply-rubber and bead-elements in band form, lnterposin between the contacting faces of the rubberized-plies material which possesses adhesion preventing qualities at normal temperatures but not at a vulcanizing temperature, shaping the band to approximately tire form, and vulcanizing.

2. That method of manufacturing tire casings which ings which consists in, assembling constit uent rubberized ply-rubber and bead-elements in band form, interposing between the bead elements and circumferentially of the contacting faces of the rubberized-plies material which has adhesion preventing qualities at normal temperatures and being fusible,

and substantially soluble in rubber at vulcanizing temperatures, shaping the band to approximately tire form and vulcanizing.

3. That method of manufacturing the cas-. ings which consists in assembling plies of rubberized fabric into band form with the surfaces of the adjacent plies in contact, ap= plying an adhesion reventing substance be tween contacting when vulcanized, shaping the band to approximately tire form, and vulcanizing. 4. That method of manufacturing tire casmgs rubberized fabric into band form with the surfaces of the adjacent plies in contact, applying to the contacting faces of the plies any 0 a group of substances which comprises zinc stearate, zinc benzoate, and zinc reslnate, sha ing the band to approximately tire form, an vulcanizing.

5. That method of manufacturing tire casconsists in assembling plies of rubberized fabric into band form with the surfaces of the adjacent plies in contact, applying to the contacting faces of the plies any of. a group of substances which comprises metallic stearates, metallic benzoates and metallic resinates, shaping the band to approximately tire form, and vulcanizing.

6. That method of manufacturing tire casings which consists in assembling plies of aces of the rubberized" plies, the substance being such that it acts as as I which consists in assembling plies of rubberized fabric into band form with the heavy metallic salts of'hydroa-romatic acids,

shaping the band to approximately tire form,

and vulcanizing. I

7. That method of manufacturm tires which consists in assembling a plum ty of .plies of rubberized fabric in superimposed relation with a lubricating coating which becomes ineffective at the vulcanizing temperature of rubber disposed between at least portions of a pair of adjacent plies, shaping the plies to conform to the shape of a tire carcass while permitting relative movement between the plies, and vulcanizing the shaped 1 plies to cause them to unite over their entire engaging surfaces.

8. That method of manufacturing tires which consists in assembling a plurality of plies of rubberized fabric in superimposed cause them to unite over their entire relation with a lubricating coating which becomes ineffective at the vulcanizing temperature of rubber dispoeedbetween at least portions of adjacent plies, shaping the plies to conform to the shape of a tire carcass while permittin relative movements between the plies, emf mlcanizing the shaped plies to engaging surfaces. 4

Signed 'at Detroit, county of Waine, State of Michigan, this 9th day ofMarc 1928.

ADRIAN O. ABBOTT,J1L 

